A lamp module for a vehicle is provided. The lamp module for a vehicle includes: a housing defining a space portion therein; a light source assembly accommodated in the housing and including a light source configured to generate light and a substrate coupled to the light source to supply a current; a light diffuser disposed above the light source assembly to diffuse irradiated light; a composite optical sheet disposed above the light diffuser and configured to realize a luminous image having a stereoscopic pattern when diffused light is incident thereon; and bezels formed on an outer circumferential surface of the housing.